A major objective of almond breeding programs is the development of new varieties with high kernel quality capable of acting as a pollinizer variety for the California almond variety ‘Nonpareil’ (non-patented in the United States). With recent findings that high proportions of the monounsaturated kernel oil, particularly oleic acid, confer significant health benefits to consumers, this trait has been included as a component of kernel quality.
Pollinizer varieties are required for ‘Nonpareil’ as well as all other commercial California almond varieties since they are self-sterile, thus requiring pollen from cross-compatible varieties for successful seed set. Because of its high market quality, ‘Nonpareil’ has become the leading California almond variety with approximately 45% of the total California acreage in 2005. Nonpareil's high market value results, in part, from its exceptional uniformity in kernel shape and composition. Nonpareil's relatively low kernel oleic acid proportion of 67.5% results in a lower phytonutrient value, greater susceptibility to kernel rancidity in storage, and poorer quality when roasted.
To provide the market with a premium quality roasting almond, California growers began planting the very high kernel-quality Spanish variety ‘Marcona’ in the mid-1990's. While consistently achieving retail market prices of approximately 4 times the ‘Nonpareil’ price, the ‘Marcona’ variety appears poorly suited for California growing conditions owing to its undesirable growth habit, greater disease susceptibility, and its very thick and hard shell which is incompatible with most California shelling equipment and results in kernel-to-nut (kernel plus shell) ratios of less than 35%.
The ‘Sweetheart’ almond is primarily an almond that would be grown and sold as a commercial nut rather than as an ornamental or ‘backyard’ tree. The most comparable example of this type of almond is the Spanish ‘Marcona’ almond variety. In California, ‘Marcona’ is grown only for commercial production of a premium quality, high market priced roasting almond. The ‘Sweetheart’ variety is targeted at the same market, as well as an effective pollinizer for ‘Nonpareil’. Currently no other almond variety combines similar characteristics with good adaptation to the California environment and production practices.
Because it is a recently introduced variety with a limited marketing niche, current plantings of the ‘Marcona’ variety in California are estimated at under 2000 acres. Plantings of the ‘Marcona’ variety in Spain are estimated to exceed 50,000 acres. It could reasonably be expected that acreage of ‘Sweetheart’ would readily increase as its greater compatibility to the California environment and processing practices are recognized. Expectation of 5000 or more acres of this new cultivar eventually being planted is probably not unrealistic.